Soil Zn Fractions Research Articles

Assessment of zinc availability to rice in mollisols of North India

The objectives of this study were to (1) characterize zinc (Zn) fractions and their relation to Zn extracted with mixed‐bed ion exchange resin capsules and (2) assess the relationships between the latter and Zn uptake by rice in 12 Mollisols from North India. The Resin Adsorption Quantity (RAQ) of Zn was measured after 1 and 14 days of anaerobic incubation. Six organic and inorganic Zn fractions were determined on anaerobic soil. Zinc uptake by rice was studied in a greenhouse experiment. Soil Zn fractions under reduced conditions followed the order residual Zn (80%)>carbonates and amorphous oxides bound Zn (12%)>weakly organically bound Zn (3%)>crystalline oxides bound Zn (2%)>strongly organically bound Zn (2%)>water soluble + exchangeable Zn (1%). RAQ‐Zn was best correlated with Zn bound to carbonates and amorphous oxides. Due to negative interactions between bicarbonate and Zn uptake, correlations between relative dry matter yield or total Zn uptake and the different Zn fractions, DTPA‐Zn measured on dry soil, or RAQ Zn were not significant. Adjusting soil test values according to soil pH improved the prediction of relative dry matter yield, but further studies are required to determine whether the resin capsule can be used as a soil test for Zn in calcareous soils.

Relação entre o zinco "disponível", por diferentes extratores, e as frações de zinco em amostras de solos

Para determinar o zinco "disponível" do solo para plantas, vários procedimentos de extração têm sido desenvolvidos. Uma alternativa utilizada no estudo de extratores do Zn "disponível" refere-se ao fracionamento do Zn total do solo, com vistas em entender suas reações no solo e o comportamento dos extratores. Este trabalho objetivou avaliar a dependência existente entre o teor de Zn disponível, por diferentes extratores, e as frações deste elemento no solo e características dos solos. Para isto, amostras de doze solos da camada de 0-20 cm de profundidade, correspondendo aos grandes grupos de Latossolo Vermelho-Escuro (LE), Latossolo Vermelho-Amarelo (LV), Latossolo Amarelo (LA), Podzólico Vermelho-Amarelo (PV) e Areia Quartzosa (AQ), receberam as doses de 0 e 20 mg dm-3 de Zn e foram incubadas por 30 dias. O Zn extraível por DTPA-TEA-CaCL2, HCl (0,1 mol L-1), Mehlich-1 (M-1) e Mehlich-3 (M-3) foi determinado. Essas amostras dos solos foram também submetidas ao fracionamento de Zn, determinando-se Zn trocável (Zntr), ligado à matéria orgânica (Znmo), ligado a óxido de manganês (ZnMn), ligado a óxido de ferro amorfo (ZnFea) e ligado a óxido de ferro cristalino (ZnFec). Concluiu-se que os extratores DTPA e M-3 revelaram maior sensibilidade às características do solo relacionadas com o fator capacidade (poder tampão). Os extratores M-1 e HCl apresentaram menor sensibilidade e menor correlação com estas características, considerando seu maior poder de extração e conseqüente menor desgaste. A relação Zn recuperado pelo extrator/Zn aplicado ao solo demonstrou ser a característica que melhor se correlacionou com características do solo relacionadas com o fator capacidade de Zn. A fração de Zn trocável foi a maior responsável pela quantidade de Zn obtido pelos extratores testados. As frações de Zntr, Znmo, ZnMn, ZnFea e ZnFec não foram suficientes para explicar, em todos os casos, o zinco recuperado pelos extratores.

Organic Waste Amendments Effect on Zinc Fractions of Two Soils

AbstractOrganic soil amendments can ameliorate metal toxicity to plants by redistributing metals to less available fractions. The objective of this study was to determine the effects of organic amendments on Zn distribution among soil fractions. Two soils (fine‐textured and coarse‐textured) were amended with five organic waste materials (some of which contained Zn) or commercial humic acid with and without 400 mg kg−1 Zn, incubated, and fractionated using a sequential extraction technique. Where no Zn was added most of the metals were in the residual fraction. Commercial compost, poultry litter, and industrial sewage sludge increased Zn in the exchangeable (EXC), organic (OM), and manganese oxide (MnOx) fractions due to Zn in the materials. Spent mushroom compost (SMC) redistributed Zn from the EXC fraction to the MnOx fraction for the coarse‐textured soil. Where Zn was added, most of the metal was in the EXC and OM fractions. The SMC and humic acid lowered Zn in the EXC fraction and increased Zn in the other fractions. Effects of the organic materials on Zn in soil fractions were more evident for the sandy soil dominated by quartz in the clay than for the finer‐textured soil dominated by kaolinite in the clay‐size fraction. It was concluded that organic materials high in Zn can increase Zn in the EXC, OM, and MnOx fractions where the soil is not contaminated and others such as SMC and HA can lower the potential availability of Zn in contaminated soils by redistributing it from the EXC to less soluble fractions.

Influence of low molecular weight organic acids on zinc distribution within micronutrient pools and zinc uptake by wheat1

Abstract A greenhouse study was conducted to examine the effects of four soil solution organic acids on the distribution of Zn within various soil micro nutrient pools and their influence on Zn uptake by wheat. L‐malic, malonic, oxalic, and succinic acids at four concentration levels, 0,10‐2 mol/L, 10‐3 mol/L, and 10‐4 mol/L were applied to pots growing wheat (Triticum aestivum) over a period of 10 weeks. A sequential Zn extraction technique was performed on the soil for each treatment, with the quantity amount of Zn in each fraction being determined using atomic absorption spectroscopy. Soil Zn fractions significantly affected by the organic acid treatments were the exchangeable, organic and Mn oxide fractions. An inverse relationship existed between Zn extracted from the exchangeable fraction and organic acid concentration for all acid treatments. Succinic and malonic acids at higher concentrations were the only treatments to be significantly higher in organic Zn compared to the control. All treatments ...

DISTRIBUTION OF ZINC FRACTIONS IN PRAIRIE SOILS

The distribution of Zn in soil fractions was determined for 27 representative prairie soils from Saskatchewan. Total Zn in the 27 soils under study ranged from 19.0 to 106.6 μg g−1 with an average of 62.0 μg g−1. A sequential fractionation showed that 0.2–2.4% of total Zn was exchangeable, 0.4–8.1% was Pb-displaceable, 0.4–4.3% was acid soluble, 1.6–9.7% was associated with Mn oxides, 0.6–4.4% was associated with organic matter and 0.9–5.1% was associated with Fe + Al oxides. Most of the total Zn was present in residual form (66.9–91.0%). Amounts of Zn in exchangeable and Pb-displaceable fractions varied inversely with soil pH and extractable P. DTPA-extractable Zn was correlated with Zn in most of the fractions, except Fe oxide-Zn, residual-Zn and total Zn. This result indicates that DTPA extractable-Zn contains Zn from Mn oxides and organic matter associations in addition to the exchangeable and adsorbed forms. The amount of total Zn was correlated with clay content and cation exchange capacity thus reflecting differences in parent materials. Key words: Soil Zn, Zn fractions, Prairie soils, pH, clay content

Contribution of Different Soil Zn Fractions to Zn Uptake By Rice

Contribution of Different Soil Zn Fractions to Zn Uptake By Rice

THE MECHANISM OF PHOSPHORUS-INDUCED ZINC DEFICIENCY IN BEAN (Phaseolus vulgaris L.)

The nature of the P-induced Zn deficiency in bean plants was studied in a growth chamber experiment using three pedogenically different soils. Application of P (0, 40, 80 and 160 mg P kg−1 soil) resulted in significant dry matter (DM) yield increases. Maximum DM yields were attained at the 40 mg P kg−1 application rate. Application of Zn (0, 5 or 10 mg Zn kg−1 soil) without P application had no effect on DM yields of bean plants. However, Zn application in combination with P application resulted in significant DM yield responses. There was no evidence that the P-induced Zn deficiency was a result of differences in soil characteristics or influence of P on the water soluble plus exchangeable, organically bound, Mn- and Fe-oxide bound or residual Zn fractions. The Zn concentration in bean plant tops was significantly reduced due to P application and the magnitude of the reduction was greatest with the first increment of applied P (40 mg P kg−1 soil). Application of P induced Zn deficiency, at least partly, by stimulation of growth and subsequent dilution of tissue Zn concentration. Translocation of Zn from roots to tops appeared to be restricted at 80 and 160 mg applied P kg−1 soil treatments, as evidenced by the reduction of Zn uptake in non-Zn treatments. Thus, plant dilution effects and reduced translocation of Zn from roots to tops were the two mechanisms responsible for the observed P-induced Zn deficiency in this study. Key words: P × Zn interaction, plant availability, plant uptake, soil Zn fractions, soil P, Zinc-65

Transformation of zinc in soils under submerged condition and its relation with zinc nutrition of rice

Laboratory and greenhouse experiments were conducted with two soilsviz., laterite and alluvial to study the transformation of applied Zn in soil fractions under submerged condition in the presence and absence of added organic matter and its relationship with Zn nutrition of rice plants.

Distribution and Availability of Zinc in Soil Fractions to Wheat on Some Alkaline Calcareous Soils

AbstractExperiments under laboratory and greenhouse conditions were conducted to investigate the response of wheat to Zn application in five loess‐derived alkaline calcareous soils and to assess the contribution of Zn in various soil fractions on its uptake by plants. Zinc in soil extracted by different reagents was also determined.Total Zn ranged from 58 to 81 mg/kg. On an average 45% of total Zn in all soil fractions was associated with sand, silt and clay. Whereas silt alone held 33% of total Zn among soil fractions in the five soils. Ammonium acetate extractable and acid residual Zn (Sand, silt and clay) explained 98% of variation of Zn in plants, and 70 or 75% of Zn in the AB‐DTPA extract and DTPA extract respectively. Application of 10 mg Zn/kg soil significantly (P < 0.01) increased plant shoot dry weight, Zn concentration and total Zn content in plants over control. Concentration of Zn in plants was significantly positively correlated with Zn extracted with DTPA and AB‐DTPA in soils.

DISTRIBUTION OF SOIL Zn FRACTIONS IN BRITISH COLUMBIA INTERIOR ORCHARD SOILS

The distribution of Zn in soil fractions was determined for 20 representative orchard soils from the British Columbia Interior. This was part of a larger study to examine Zn availability to fruit trees. Medium to high levels of total soil Zn were measured (51.5–226.3 mg kg−1) with an average of 89.7 mg kg−1. A sequential fractionation showed that 0.3–23.2% of total soil Zn was exchangeable, 0.5–29.7% was associated with organic matter, 1.3–15% was associated with Fe + Al oxides and 45.6–92% was residual. A separate determination indicated that 6.4–24% soil Zn was associated with Mn oxides. Except for the Fe + Al oxide fraction for which no correlations were made, amounts of Zn in the fractions were significantly positively correlated with total Zn, and also, with Bray P1 extractable P and organic matter content. Zinc in the exchangeable and organic fractions was negatively correlated with both pH and residual Zn. This suggested a redistribution of soil Zn from the residual fraction into the exchangeable and organic fractions with acidification. For exchangeable Zn this was further evidenced in the much smaller amounts of Zn extracted by M NH4OAc (pH 7.0) than by M MgCl2 from acid soils. The observed range of total Zn and exchangeable Zn suggests that a wide range of Zn availability could exist in B.C. Interior orchard soils. Key words: Soil Zn, Zn fractionation, orchard soils, pH × exchangeable Zn interaction